Technical Abstract:
The registration of transgenic corn with resistance to corn rootworm larval feeding offers a viable alternative to insecticides for managing the most economically important insect pest of corn. Maintaining susceptibility to transgenic crops (resistance management) is in the interest of growers, the Environmental Protection Agency, and industry, but requires an understanding of corn rootworm biology that does not currently exist. In recent years, we have conducted a series of experiments on the basic biology of the western corn rootworm with an eye toward resistance management. We have documented that larvae can move at least three plants down the row and across narrow-row corn. We have examined the host status of 60 grass species and demonstrated that western corn rootworm larvae can survive for at least 24 days on almost all grasses tested. More recently, we have examined interactions between alternate hosts, YieldGard Rootworm resistant maize, and the timing of glyphosate sprays. These data will be reviewed and discussed in terms of resistance management with the currently registered product and other potential products. This information will be important to seed companies, the Environmental Protection Agency, and modelers in their attempts to develop resistance management plans for transgenic corn by providing more realistic assumptions in current mathematical models.